Subaru Forester Owners Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
43 Posts
Discussion Starter · #1 ·
Every Forester/Subaru front diff change video I've watched has shown an overflow plug which needs drained and then monitored for dripping to know when you've refilled it enough. However, none of the videos were a 2012 Forester and mine does not have any of these plugs shown which are to the side of the main diff drain. All I could find was a bolt between the transmission and front diff. I removed it thinking it must be the diff overflow, but I'm pretty sure what came out was a small amount of trans fluid. I can find no mention online of a trans overflow plug. So what did I pull? Was this actually the diff overflow? When I thought trans fluid came out, I put the plug back in and left it and just filled the diff to the full line on the dipstick.

I'm wondering if maybe this plug right between the trans and diff is a shared overflow plug? Is that even done with separate trans & diff?

Is filling to the fill line ok for the diff? I was going to measure what I took out but I didn't have my pan positioned like I thought I did and missed most of it.

And one last question. I don't need limited slip additive for this vehicle, correct? The parts guy at the dealer told me no and I have found nothing indicating I need anything other than the Subaru 75-90 gear oil. But then I was looking over my 60k maintenance invoice from 4 years ago and they have limited slip additive on there.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #2 ·
I found a pretty skimpy service manual online which shows both the front diff and transmission fluid change procedures and neither reference this plug between them. The plug can be seen in a diagram on another page but again, no reference is made. It really smelled like trans fluid that came out. Maybe a few ounces. The dipstick level didn't change.

I wonder if it's some kind of service port. Or if maybe it is the trans check plug but isn't used in the official fluid change. I know other models have a fill plug on the side which also works as the check plug but I didn't see one on mine. Will look closer. This service manual has both diff and trans being filled from their dipstick holes and using the dipstick to determine proper fill. Which is easy on the diff but I can never get a reasonable read on the trans. Right now it's reading at lower hole but also has fluid smeared way up it which makes me unsure if it's actually low. I hate this dipstick.
 

·
Premium Member
2019 Crosstrek 2018 Forester XT
Joined
·
14,789 Posts
Just a drain. Fill thru dipstick. You are probably looking at manual transmission

Make sure you know what dipstick is which. Auto transmission on driver side . Differential in middle toward passenger side. Auto tranny checked hot and running in neutral

Front diff is 1.1 quart. Rear is .9 quart of 75W-90 gear oil.

TrAnny drain is hex bolt on flat pan. Diff is torx plug


From t
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #4 ·
Thanks for the reply. Mine's an auto and has some kind of plug in the center right where the tranny and diff meet. Any idea what that is? It's not a drain as only a little ATF came out and then it stopped and the level didn't go down.

Yeah, that's what I ended up doing. Had a heck of a time getting the diff plug out. Just did the front so far. Will do the rear when I get back from a trip.

I did make sure to get the dipstick and drain plugs right. I didn't want to go draining my tranny. I'm just really curious about what bolt that was I pulled thinking it was the diff overflow. And a little concerned that I don't know what it is, having pulled it.

I'm having a hard time reading the tranny stick. I'm doing it while hot and I run through all the gears first but the stick is a mess every time I take it out. If I'm just going by whether there is fluid in the holes, then it's showing I'm at the low hole. But there is fluid on the stick going up higher so if I go by that, it's good. I have a quart I can top off with but I'm concerned about over filling it so I've held off doing that.

Tranny fluid was flushed at dealer a couple years ago so I'm good on that for a while. But the front diff looked super simple so I decided to do it myself. And it would've been had it not been for there being no diff overflow plug and instead I pulled a mystery one.
 

·
Registered
2012 Forester X Auto
Joined
·
2,494 Posts
@rnranimal -

No idea what you are talking about re the bolt you removed, as there are lots of bolts down there, but it obviously it isn't a differential overflow because there isn't one in front.
If /when you change the rear, make SURE you remove the overflow (upper) plug first, before the drain plug is removed.
Removing the overflow allows the diff to drain faster, but more importantly, if you remove the drain and you can't get the overflow plug out, there is no way to refill the differential, and you just created a car that can't be driven.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #6 ·
@rnranimal -

No idea what you are talking about re the bolt you removed, as there are lots of bolts down there, but it obviously it isn't a differential overflow because there isn't one in front.
If /when you change the rear, make SURE you remove the overflow (upper) plug first, before the drain plug is removed.
Removing the overflow allows the diff to drain faster, but more importantly, if you remove the drain and you can't get the overflow plug out, there is no way to refill the differential, and you just created a car that can't be driven.
Yeah, I’ll definitely make sure I can crack the fill before pulling the drain.

Here are a couple pics of the bolt. It really seems like some kind of drain where it's located and being angled like it is. I’ve just driven over 600 miles over 2 days with no issues so I don’t think I harmed anything. Out of curiosity, I pulled that bolt again the next day after pulling it the first time and a little more tranny fluid came out so more found its way in there after just a short drive. Whatever it is.
 

Attachments

·
Registered
2012 Forester 4 speed auto
Joined
·
1,128 Posts
I believe the front differential drain plug and over flow are on the bottom not on the side for the 2012 Auto. The plugs are located just below the CV joints. Also the front differential is filled through the dip stick. Good luck. Be careful you don't accidentally drain your transmission. Automatics have separate lubrication of the tranny and the differential.
 
1 - 7 of 7 Posts
Top